1. Field of the Invention
The present invention relates to a touch type electrophoretic display device and, more particularly, to a touch type electrophoretic display device capable of minimizing the number or size of gate drivers by minimizing the number of gate lines.
2. Description of the Related Art
In general, an electrophoretic display device is an image displayer using a phenomenon that when a pair of electrodes receiving voltage are put in a colloid solution, colloid particles are moved to one polarity.
The electrophoretic display device is a display device in which a transparent conductive film is coated on a base film which is thin and can be easily bent like paper or plastic to drive electrophoretic suspension and receives much attention as electric paper that may replace the conventional printing mediums such as books, newspapers, and the like.
The electrophoretic display device is advantageous in that it can be easily carried around because it does not need a backlight and has good flexibility. Recently, research for a model emphasizing portability by adding a touch function to the electrophoretic display device is actively ongoing.
The touch type electrophoretic display device will now be described with reference to the accompanying drawings.
An electrophoretic panel provided in a general touch type electrophoretic display device as shown in FIG. 1 includes a first substrate 1 on which first gate lines GL11˜GL1m and data lines DL1˜DLn cross to define a plurality of pixels, and a second substrate (not shown) disposed to face the first substrate 1.
With reference to FIG. 2, on the first substrate, a plurality of second gate lines GL21˜GL2m are formed to be parallel to the first gate lines GL1˜GL1m,a plurality of sensing signal lines SL1˜SLn are formed to be parallel to the data lines DL1˜DLn, and a plurality of first and second touch driving voltage lines 3 and 4 are formed to be parallel to the first and second gate lines GL11˜GL1m and GL21˜GL2m. A driving thin film transistor (TFT_D), a pixel electrode 5, a switching TFT (TFT_S), a photo TFT (TFT_P) are formed at each pixel.
The driving TFT (TFT_D) is formed to be connected to the first gate lines GL11˜GL1m and the data lines DL1˜DLn, the pixel electrode 5 is formed to be connected to the driving TFT (TFT_D) within a corresponding pixel, the switching TFT (TFT_S) is formed to be connected to the second gate lines GL21˜GL2m and the sensing signal lines SL1˜SLn, and the photo TFT (TFT_P) is formed to be connected to the first touch driving voltage line 3 and the switching TFT (TFT_S). Here, whether the photo TFT (TFT_P) is turned on or off or a flow amount of the photo TFT (TFT_P) are determined according to the amount of light.
Although not shown, a common electrode (not shown) is formed on the second substrate, and an electrophoretic film (not shown) is formed between the first substrate 101 and the second substrate.
With reference to FIG. 1, the general touch type electrophoretic display device includes a driving unit for driving the electrophoretic panel. The driving unit includes a timing controller 10, a first gate driver 12a, a second gate driver 12b,a data driver 13, and a lead-out driver 14.
The timing controller 10 generates a gate control signal by using a signal inputted from an external source (e.g., system) and outputs the gate control signal to the first and second gate drivers 12a and 12b, generates a data control signal and outputs it to the data driver 13, and outputs a pixel voltage which has realigned image data inputted from the external source (e.g., system) to the data driver 13.
The first gate driver 12a drives the first gate lines GL11˜GL1m by using the gate control signal from the timing controller 10, the second gate driver 12b drives the second gate lines GL21˜GL2m by using the gate control signal from the timing controller 10, and the data driver 13 receives a data control signal and a lo pixel voltage from the timing controller 10 and supplies the pixel voltage to the data lines DL1˜DLn according to the data control signal.
When the photo TFT (TFT_P) is operated according to a user touch and a sensing signal is transferred via the switching TFT (TFT_S) and the sensing signal lines (SL1˜SLn) within a corresponding pixel, the lead-out driver 14 outputs touch data obtained by detecting the position of the photo TFT (TFT_P), namely, coordinates of a touched portion, to the timing controller 10. Upon receiving the touch data, the timing controller 10 supplies a pixel voltage for converting an image in relation to the user touched portion to the data driver 13.
In the general touch type electrophoretic display device constructed as described above, the second gate lines GLS1˜GL2m are additionally formed to drive the photo TFT (TFT_P) formed to provide the touch function. Thus, compared with an electrophoretic display device without a touch function, the touch type electrophoretic display device is disadvantageous in that it has a significantly larger number of gate lines and it needs the second gate driver 12b to drive the second gate lines GL21˜GL2m. 